Automatic telephone-exchange system



J. L. McQUARRlE. AUTOMATIQ TELEPHONE EXCHANGE SYSTEM.

APPLICKTION FILED JULY 2119!].

Patented Apr. 20, 1920.

//1ven/0/ James L. M Quark/e Q mobuzzou UNITED STATES PATENT OFFICE.

JAMES II- MOQUARRIE, 6F MONTCLAIR, IIE'W JERSEY, ASSIGNOR TO WESTERNELECTRIC COMPANY, INCGRPGRATEID, OF NEW YORK, N. 1., A CORPORATION OFNEW YORK.

AUTOMATIQ TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Apr. 20, 1920.

Application filed July 2, 1917. Serial No. 178,234.

To all whom it may concern:

Be it known that I, JAMEs L. MCQUAR- RIE, a citizen of the UnitedStates, residing at Montclair, in the county of Essex and State of NewJersey, have invented certain new and useful Improvements in AutomaticTelephone-Exchange Systems, of which the following is a full,iclear,concise, and exact description.

This invention relates to automatic telephone exchange systems, and moreparticu larly to an arrangement for controlling the operations of theselective switches employed in such systems.

It is the object of the present invention to provide means whereby atrain of automatic switches may be controlled by a single auxiliarycontrolling switch.

A feature of the invention is the provision of an auxiliary controllingswitch at the first switch of a train of selective switches, thisauxiliary switch serving to control the various operations not only withthe switch with which it is associated, but also of the succeedingswitches with which it is successively associable.

The invention has been shpwn applied to a system of the well-knownstep-by-step full automatic type, but it is to be understood that theinvention is not to be restricted to any particular system, since theinventive idea may be applied to a large variety of systems.

Referring now to the drawing, there is illustrated a circuit arrangementsuitable for operating a train of automatic switches in accordance withthe features of the present invention.

The structure of the auxiliary circuit con trolling switch has not beendisclosed, the arrangement including merely a plurality of wipersmounted on a common shaft and arranged to be successively advanced intostopping positions under the control of an escapement magnet, upon eachdeenergization of such controlling escapement magnet. Since switches ofthis general type are well known, it has not been'considered necessaryto specifically disclose the structure of this switch. The switch isarranged to be mechanically restored to normal when the first selectorswitch returns to its normal position.

The selective switches whose operating circuits are shown, may be ingeneral any well-known type of step-by-step switch arranged for motionin two directions under the control of primary and secondary steppingmagnets.

It is thought that the invention will best be understood by describingthe operation of the circuits as utilized in setting up a call between acalling and a called subscriber.

If the subscriber whose substation is indicated at A desires aconnection with a subscriber whose substation is indicated at B, he willremove his receiver from the hook, whereupon his line will be extendedto the first selector shown in the drawing in any well-known manner, itbeing assumed in the present case that a line finder, whose brushes areindicated at l and 2, is utilized for this purpose.

As soon as the calling line is extended to the first selector, linerelay 3 is energized by means of a circuit extending from groundedbattery, right-hand winding of relay 3, finder brush 2 and itsassociated contact, the loop of the calling subscribers line finderbrush 1 and its associated contact, lefthand winding of the line 3, toground. The resultant energization of line relay 3 com pletes a circuitfrom grounded battery,

'inding of slow-release relay l, armature and front contact of relay 3to ground. lVhen the subscriber operates his sending device indicated at5 to transmit the first series of impulses, line relay 3 will beintermittently de'e'nergized in response to such impulses. Upon thefirst denergization of line relay 3 a circuit is closed from groundedbattery, winding of slow-release relay 5, right-hand armature and frontcontact of relay 4, which being slow to release, maintains its armaturesduring the sending of impulses, armature and back contact of relay toground. At the same time a parallel circuit is completed from groundedbattery the primary stepping magnet 6 of the first selector, side-switchwiper 7 in its first position, right-hand armature and front contact ofrelay 4, armature and back contact of relay 3, to ground. Magnet 6 isenergized in this circuit and moves the first selector brush shaft onestep in a primary or group selecting direction. The energization ofrelay 5 completed a circuit from grounded battery, winding of escapemagnet 8, side-switch wiper 9 in its first po sition, conductor 10,right-hand armature and front contact of relay 5, to ground. The escapemagnet is energized but does not release the side switch. Relay 5 beingslow to release retains its armatures during the sending of the firstset of impulses in response to which the stepping magnet 6 isintermittently energized to advance the brush set into operativerelation with the group of trunks leading to a second selector servingconnectors through which the desired line maybe reached.

Upon the completion of the first series of impulses, line relay 3remains energized for a comparatively long interval, and relay isdeenergized, causing in turn the denergization of escape magnet 8, whichupon deenergization releases the side switch into its second position.In the second position of the side switch, a circuit is completed forescape magnet 8 from grounded battery, winding of magnet 8, side-switchwiper 9 in its second position, conductor 11, sideswitch wiper 12 in itssecond position, and secondary off-normal contact 13, to ground. At thesame time a circuit is completed from grounded battery, winding ofsecondary stepping magnet 14, its armature and back contact, conductor15, side-switch wiper 16 in its second position, armature and frontcontact of line relay 3, to ground. Stepping magnet 14 interrupts itsowncircuit to advance the brush set over the trunk terminals in theselected grpup until an idle trunk is found. If we assume that busytrunks are characterized by the presence of ground on their testcontacts 17, escape magnet 8 will remain energized until an idle trunkis found, since although the path to ground by way of off-normal contact13, which is opened as soon as the switch makes its first secondarystep, is broken, an alternate holding path will be found by way ofconductor 18, test brush 19 and test terminal 17, to ground. As soon astest brush 19 encounters a contact corresponding to 17 which is freefrom ground, escape magnet 8 will be deenergized and will release theside switch into position three, opening the circuit of stepping magnet14 and bringing the brush set to rest on the terminals of an idle trunk.When the side switch moves into position three, ground is supplied totest terminal 17 from ground, side-switch wiper 12 in its thirdposition, conductor 18 and brush 19, to render this line non-selectableto other hunting selectors. This protecting ground is maintained onterminal 17 through the successive positions of the side switch, andmaintains the trunk busy until the side switch has been restored to itsnormal position.

The calling subscriber now operates his sender 5 to transmit a secondseries of impulses. As before, the first deenergization of relay 3completes a circuit for slow-release relay 5, causing in turn theenergization of escape magnet 8 over a circuit traceable from groundedbattery, winding of magnet 8, side-switchwiper 9 in its third position,conductor 10, right-hand armature and front contact of relay 5, toground. Primary steppingmagnet 20 at the second selector isintermittently energized in response to the vibration of the armature ofline relay 3 over a circuit extending from grounded battery, winding ofstepping magnet 20, contact 21, brush 22, conductor 23, side-switchwiper 7 in its third position, right-hand armature and front contact ofslow-release relay 4, armature and back contact of relay 3, to ground.Upon the termination of the second series of impulses, relay 3 remainsenergized for a relatively long period of time, causing as before thedeenergization of relay 5. When relay 5 deenergizes, escape magnet 8 isdeenergized in turn, allowing the side switch to be released into itsfourth position.

In the fourth position of the side switch, escape magnet 8 is energizedover a circuit from grounded battery, side-switch wiper 9 in its fourthposition, conductor 24, sideswitch wiper 25 in its fourth position,conductor 26, brush 27, contact 28, conductor 29, to ground by way ofsecondary off-normal contact 30. At the same time a circuit is completedfor the secondary stepping magnet 89 of the second selector fromgrounded battery, armature and back contact of magnet 89, contact 31,brush 32, sideswitch wiper 16 in its fourth position, armature and frontcontact of relay 3, to ground. Stepping magnet 89 interrupts its owncircuit and causes the second selector brush set to be advanced over aselected group of trunks in search of an idle trunk line therein. Assoon as the second selector moves away from its normal secondaryposition, off-normal contact 30 is opened, but an alternate holdingcircuit for escape magnet 8 is found as long as test brush 33 encountersthe test contacts of busy lines, which are characterized, as in the caseof the first selector, by the presence of ground potential on their testcontacts. This circuit extends from grounded battery, winding of magnet8, side-switch wiper 9 in its fourth position, conductor 24, side-switchwiper 25 in its fourth position, conductor 26, brush 27, contact 28,brush 33, test contact 34, to ground. As soon as brush 33 encounters acontact 34 associated with an idle trunk line, the absence of groundallows the escape magnet 8 to denergize, moving the side-switch wipersfrom position 4 to position 5 and therefore opening at wiper 16 thepreviously traced circuit for stepping magnet 89. The brush set istherefore brought to rest on the terminals of the trunk leading to anidle connector switch serving lines including that of the desiredsubscriber. lVhen the side switch is moved into its fifth position,ground is supplied to test contact 34 from ground, side-switch wiper 25is in its fifth position, conductor 26, brush 27, contact 28 and testbrush 33, in order to render this line non-selectable to other huntingselectors. This ground is maintained throughout the succeeding positionsof the side switch.

The calling subscriber now sends a third series of impulses to operatethe seized connector switch in its primary movement. Upon the firstdeenergization of relay 3, slowrelease relay 5 is energized as before,causing in turn the energization of escape magnet 8. At the same time acircuit is completed from grounded battery, winding of primary steppingmagnet 35 of the connector, contact 36, brush 37, contact 38, brush 39,conductor 40, side-switch wiper 7 in its fifth position, right-handarmature and front contact of relay 4, armature and back contact ofrelay 3, to ground. Stepping magnet 35 is intermittently energized inresponse to the vibration of the armature of line relay 3, to advance aconnector brush set into operative relation with a desired group. Uponthe completion of the series of impulses, line relay 3 is maintainedenergized for a relatively long interval and slow-release relay 5dee'nergizes, causing in turn the cleenergization of escape magnet 8,which by deenergizing moves the side switch out of its fifth and intoits sixth position.

When the calling subscriber sends the final series of impulses,slow-release relay 5 is energized to control escape magnet 8 as beforedescribed. In this case, secondary stepping magnet 41 of the connectoris operated in response to the operation of line relay 3 over a circuitfrom grounded battery, winding of stepping magnet 41, contact 42, brush43, contact 44, brush 45, conductor 46, side-switch wiper 7 in its sixthposition, right-hand armature and front contact of relay 4, armature andback contact ofv relay 3, to ground. Upon the termination of this seriesof impulses, relay 5 is rle'energized, and if the desired line is idle,as will be assumed in the present case, escape magnet 8 will bedeenergized to allow the side switch to be released into its seventhposition.

In position 7 of the side switch, a circuit is completed from groundedbattery, winding of escape magnet 8, side-switch wiper 9 in its seventhposition, conductor 47, armature and back contact of ringing cut-offrelay 48, to ground. A circuit is then completed from ground, ringinggenerator 49, winding of relay 48, armature and front contact of escapemagnet 8, conductor 50,

sideswitch wiper 51 in its seventh position, brush 52, contact 53, brush54, contact 55, brush 56, contact 57, the loop of the called subscribersline, contact 58, brush 59, contact 60, brush 61, contact 62, brush 63,sideswitch wiper 64 in its seventh position, to ground. lVhen the calledsubscriber responds by removing his receiver from the switchhook, theresistance of this circuit will be sufliciently lowered to allow relay48 to energize, thereby opening the circuit of escape magnet 8 andallowing this magnet to deenergize and release the side switch into itseighth position. In the eighth position of the side switch, talkingcircuit is completed to the called subscriber by way of wipers 51 and64, battery being supplied to the called line through the windings of afeed coil 65.

As soon as the side switch moved into its seventh position, guardingpotential is sup plied to the test contact 66 of the called line fromground, side-switch wiper 67 in its seventh position, conductor 68,brush 69, contact 70, brush 71, contact 7 2, and brush 73, to renderthis line busy to other con-- nectors. This ground is also maintained inthe final position of the side switch.

If the desired line had been busy, escape magnet 8 would not have beendeenergized upon the completion of the final series of impulses, since aholding circuit would exist, from grounded battery, winding of escapemagnet 8, conductor 74, side-switch wiper 67 and its sixth contact,conductor 68, brush 69, terminal 70, brush 71, contact 72, brush 73, andmultiple contact 66 to ground. Escape magnet 8 would therefore notrelease the side switch into its seventh position.

In parallel with the above traced circuit, a circuit would be completedfrom grounded battery, left-hand armature and back contact of relay 5,winding of busy relay 75, conductor 74, to ground over the pathdescribed. Relay 75, upon energization, locks up through its left-handarmature and front contact to ground at the left-hand armature and frontcontact of relay 4. At the same time an induced alternating current issupplied to the windings of coil 65 over a path from ground,-busy toneapparatus 7 6,-righthand armature and front contact of relay 7 5, toground through the right-hand winding of coil 65. The inductive actionof this current on the windings of coil 65 causes alternating current tobe transmitted through the condensers 77 and 78 to the callingsubscribers substation, and will produce a characteristic tone in hisreceiver to inform him that the desired line is busy. He will thereuponreplace his receiver upon the hook and cause the release of the switchesin a manner now to be described.

When the calling subscriber replaces his receiver, relay 3 isdecnergized and causes after a short interval, the deenergization ofslow-release relay 4. Parallel circuits are then completed for releasemagnets 7 9, 80 and 81 respectively, by way of the righthand armaturesand back contacts of relays 4 and 3. The circuit of release magnet 81extends from grounded battery, winding of release magnet 81, off-normalcontact 82, terminal 83, brush 84, contact 85, brush 86, oilnormalcontact 87, right-hand armature and back contact of relay 4, armatureand back contact of relay 3, to ground. The circuit of release ma et 80extends from grounded battery, winding of release magnet 80, offnormalcontact 88, contact 85, brush 86, to ground over the path described. Thecircuit of releasev magnet 79 extends from grounded battery by way ofoff-normal contact 87, to ground, as described. In each case the releasemagnet attracts its armature and locks itself to ground until the switchis fully restored, at which time the associated off -normal contact willbe opened. The restoration of the first selector causes the restorationof the controlling side switch. The line finder switch whose brushes areindicated at l and 2, may be restored in any well-known manner inaccordance withthe type of finder used.

It is to be observed that the release of the switches will beaccomplished in the same manner regardless of the point of operation atwhich the calling subscriber desires to release the connection, since atany time that relays 8 and 4 deenergize, release circuits will becompleted for the magnets of any switches which have been operated.

What is claimed is:

1. In a telephone exchange system, calling and called subscribers lines,a plurality of switch devices for interconnecting a calling and a calledline, a test circuit for each of said switch devices, and a test relaycommon to said test circuits.

2. In a telephone exchange system, calling and called subscribers lines,a plurality of switch devices for interconnectin a calling and a calledline, a test circuit Ior each of said switch devices, and a test relaylocated at one of said switch devices and common to said test circuits.

3. In a telephone exchange system, calling and called subscribers lines,a train of switch devices for interconnecting a calling and a calledline, a test circuit for each of said switch devices, and a test relayassociated with the first switch of the train and common to said testcircuits.

4. In a telephone exchange system, calling and called subscribers lines,a first selector,

a second selector, a connector switch for interconnecting said lines, atest circuit for each of said switch devices, and a test relayassociated with the first selector and common to said test circuits.

5. In a telephone exchange system, calling and called subscribers lines,a train of switch devices for interconnecting a calling and a calledline, a test circuit for each of said switch devices, and an auxiliaryswitch and test relay common to said test circuits.

6. In a telephone exchange system, calling and called subscribers lines,a train of switch devices for interconnecting a calling and a calledline, a test circuit for each of said switch devices, and an auxiliaryswitch common to said test circuits.

7. In a telephone exchange system, calling and called subscribers lines,a train of switch devices for interconnecting a calling and a calledline, a test circuit for each of said switch devices, an auxiliaryswitch located at the first switch device of the train, and a testrelay, said test relay and auxiliary switch being common to said testcircuits.

8. In a telephone exchange system, calling and called subscribers lines,a train of switch devices for interconnecting a calling and a calledline, a test circuit for each of said switch devices, a single testrelay, and means for successively associating said test relay with thetest circuits of the switch devices.

9. In a telephone exchange system, calling and called subscribers lines,a train of switch devices for interconnecting a calling and a calledline, a stepping relay associated with the first switch of said train, atest circuit for each of said switch devices, a test relay common tosaid test circuits, a release magnet associated with each switch device,and release circuits for said switch devices independent of said testcircuits, all including the armature of said stepping relay.

10. In a telephone exchange system, calling and called subscriberslines, a train of switch devices for interconnecting a calling and acalled line, including a stepping magnet associated with the firstdevice of said train, a test circuit for each of said switch devices, atest relay common to said test circuits, a release magnet associatedwith each switch device, and release circuits for said switch devicesindependent of said test circuits, all including the armature of thestepping magnet associated with the first switch device of the train.

In witness whereof I hereunto subscribe my name this 29th day of June,A. D. 1917.

JAMES L. MOQUARRIE.

